Symptom: Left-Sided Ear Drainage

The patient is a 72-year-old female with a history of left-sided ear drainage. Despite receiving ear drops, her symptoms did not improve. Notably, she has a history of right ear surgery in 1991 and left ear surgery in 2016. Her medical history reveals hearing loss, dizziness, migraine, anxiety, and depression. The microscopic examination of the ears revealed mucosalization in the posterior superior quadrant area of the right ear. On the left side, findings included bulging of the posterior lateral canal, which was soft when palpated with a curette (see Figure 1). However, no primary cholesteatoma was evident at the TM level. Her audiogram showed moderate-to-severe high-frequency hearing loss on the right and mild down-sloping to profound hearing loss on the left.Figure 1: Image of patient’s left tympanic membrane. Left-sided ear drainage, iatrogenic cholesteatoma, lateral canal flap, case study.Figure 2: Axial (horizontal) CT of the temporal bones showing the mass in the lateral left canal (right side of images). Left-sided ear drainage, iatrogenic cholesteatoma, lateral canal flap, case study.Figure 3: Coronal (parallel to the face) CT of the temporal bones showing the mass in the lateral left canal, which does not invade the mastoid. Left-sided ear drainage, iatrogenic cholesteatoma, lateral canal flap, case study.Figure 4: Sagittal (vertical parallel to the ear) CT of the temporal bones demonstrating the mass in the lateral left ear canal. Left-sided ear drainage, iatrogenic cholesteatoma, lateral canal flap, case study.Figure 5: On the left, axial (horizontal) CISS MRI shows hyperintensity (brighter than brain) in the ear canal. On the right, axial (horizontal) T1-weighted post-gadolinium MRI showing the mass in the ear canal is isointense (same color as brain). Left-sided ear drainage, iatrogenic cholesteatoma, lateral canal flap, case study.Figure 6: Coronal (parallel to the face) T2-weighted MRI showing hyperintensity (brighter than brain) mass in the left ear canal. Left-sided ear drainage, iatrogenic cholesteatoma, lateral canal flap, case study.Diagnosis: Iatrogenic Cholesteatoma Arising From the Lateral Canal Flap Najva Mazhari, MD; Karen Tawk, MD; Mehdi Abouzari, MD, PhD; and Hamid R. Djalilian, MD At first look, the mass in the ear canal appears to be a smooth-walled mass. While, in other parts of the body, this can be assumed to be a benign mass, we should always keep in mind that patients can have a subcutaneous carcinoma in the ear canal, which can cause a smooth appearance on the surface. This type of tumor originates in the ceruminous glands and is termed adenoid cystic carcinoma, or ceruminous cystadenocarcinoma. Therefore, a smooth-walled mass in the cartilaginous ear canal should be viewed with suspicion. In the bony canal, a smooth-walled mass is generally caused by exostosis. One way to help identify the character of the mass is to gently palpate the mass with a curette. A hard mass with a bony consistency is most likely an exostosis if it is in the bony ear canal or an osteoma if it is at the junction of the bony canal and cartilaginous ear canal. Exostoses are usually multiple in origin and occur as a result of long-term cold air and water exposure. This is most commonly seen in surfers, since they spend a long time in open water with the wind blowing on their wet ear canal. Osteomas of the ear canal are benign tumors of bone and tend to occur at the bony cartilaginous junction and are singular lesions and not multiple like exostoses. Cholesteatomas are, at their most basic definition, the occurrence of squamous epithelium (skin) in areas of the temporal bone where it does not belong. That can be in the middle ear, the mastoid, the petrous apex, or other epidural or intracranial locations.1–4 Rarely, cholesteatomas can occur in the bony ear canal. This form of cholesteatoma is generally seen in the elderly, and most likely occurs as a result of trauma to the ear canal, which causes slow erosion and the migration of the skin into the bony ear canal. This problem progresses over time, creating the appearance of an excavated ear canal. This condition is most commonly seen on the floor of the ear canal but can be seen in the anterior or posterior ear canals. Superior ear canal cholesteatomas are rare. This is most likely because when Q-tips or other objects are placed into the ear canal, they will first contact the floor of the ear canal as it is more convex and more prominent. A superior ear canal wall cholesteatoma is rare because that area does not tend to get traumatized. Unlike cholesteatomas of the middle ear and mastoid, which tend to be filled with keratin, external canal cholesteatomas, do not have a significant accumulation of keratin, but rather the most prominent feature is the presence of sequestrum or dead bone for unknown reasons. As the cholesteatoma starts digging into the ear canal wall, it tends to excavate bone from the ear canal, and that bone is deposited into the ear canal. While there may be an accumulation of some keratin from the natural migration of keratin, which gets interrupted at the area of the sequestrum, significant keratin accumulation is not a prominent feature of cholesteatoma of the external auditory canal. Granulation tissue is commonly seen around the area of the cholesteatoma. If large amounts of keratin are seen in the ear canal, then the patient is more likely to have keratosis obturans. Keratosis obturans is a rare condition of the ear canal, which leads to the accumulation of keratin due to a lack of natural migration of the dead skin (keratin). While this accumulation of keratin can lead to erosion of the ear canal wall bone, it does not cause sequestrum formation. In both keratosis obturans and canal cholesteatoma, the area of debris and sequestrum are visible and would not be hidden under intact skin. In this case, the mass appears to be hidden behind normal canal skin. When faced with a mass in the ear canal, generally imaging is obtained to better understand the origin to allow for more accurate diagnosis and treatment. Computed tomography (CT) scans of the temporal bone provides much more detail of the bony anatomy, and in a patient with previous surgery, it allows for a better understanding of what was previously performed in surgery. Whenever we see a smooth-walled, soft mass in the ear canal after surgery, we must always consider iatrogenic (caused by the surgeon) cholesteatoma as a differential diagnosis. This problem can occur when aligning tissues, and some skin or skin-lined tissue becomes hidden under another tissue, most commonly other skin. When performing a tympanoplasty operation, an incision is made in the ear canal, and the lateral and medial skin flaps are raised (separated) from the canal bone. At the end of the surgery, these two pieces of skin (lateral and medial flaps) must be realigned and unfurled to ensure that keratin-lined skin does not get caught under other skin. Skin is made up of squamous epithelium. This type of tissue is constantly making new skin and sheds the dead layers of skin. Therefore, if skin or squamous lined tissue, such as the canal skin or tympanic membrane is hidden under other tissues, it will accumulate the dead skin keratin and lead to cholesteatoma formation. Early on, these are termed keratin pearls as they form a small ball which can be popped with an instrument in the office. In this patient, the CT scans of the temporal bones were obtained, which showed a mass in the ear canal with no involvement of the bony structures of the ear canal or mastoid (Figures 2-4). This was encouraging, and it appeared that the mass is self-limited, and most likely benign in origin. While a CT scan cannot differentiate the character of the mass, magnetic resonance imaging (MRI) can generally differentiate a cholesteatoma from other types of mass. In this patient, the MRI showed that the mass was isointense (same color as a brain) on T1-weighted images. It showed that it was hyperintense (brighter than the brain) on T2-weighted images (Figures 5 and 6). These findings suggest that the tissue is most likely cholesteatoma in origin. While a fluid-filled mass can have a similar appearance on MRI, it would be unexpected that a fluid-filled mass would be as solid on palpation compared to a cholesteatoma. Once the diagnosis of iatrogenic cholesteatoma has been established, the next step is deciding on treatment options. In a patient like this, observation is not a great idea as the mass will continue to grow and will eventually invade the canal bone. Excision of mass or marsupialization are the best options. The patient opted for marsupialization, which is the removal of the outer wall of the mass. This allows the keratin to be removed from inside the mass and the inner wall, which is lined by the skin, will become integrated into the canal skin and continuous with it. The patient opted for an office procedure, and this was performed under local anesthesia without difficulty. BONUS ONLINE VIDEOS: VISUAL DIAGNOSIS Read this month’s Clinical Consultation case, then watch the accompanying videos from Hamid R. Djalilian, MD, to review the patient’s imaging for yourself. Video 1. Axial (horizontal) CT of the temporal bones showing the mass in the lateral left canal Video 2. Coronal (parallel to the face) CT of the temporal bones shows the mass in the lateral left canal which does not invade the mastoid Video 3. Sagittal (vertical parallel to the ear) CT of the temporal bones demonstrating the mass in the lateral left ear canal Video 4. Axial (horizontal) CISS MRI showing hyperintense (brighter than brain) mass in the ear canal Video 5. Axial (horizontal) T1-weighted non-contrast MRI showing the mass in the ear canal Video 6. Coronal (parallel to the face) T2-weighted post gadolinium MRI showing the hyperintense (brighter than brain) mass in the left ear canal Watch the patient videos online at thehearingjournal.com.